Coupling members for pipe machining apparatuses

ABSTRACT

Pipe machining apparatuses, coupling members, and methods of assembling pipe machining apparatuses are provided. In one aspect, a coupling member for coupling together a first section and a second section of a pipe machining apparatus includes a first housing member adapted to couple to the first section, a second housing member adapted to couple to the second section, an arm movably coupled to the first housing member, and an engagement member coupled to the arm. The arm is adapted to move between a coupled condition, in which the engagement member engages the second housing member, and an uncoupled condition, in which the engagement member does not engage the second housing member.

RELATED APPLICATIONS

The present application is a continuation-in-part of U.S.Non-Provisional patent application Ser. No. 13/796,121, filed Mar. 12,2013, which claims the benefit of U.S. Provisional Patent ApplicationNo. 61/709,571, filed Oct. 4, 2012, the contents of all of which areincorporated by reference herein.

FIELD OF THE INVENTION

The present disclosure generally relates to pipe machining apparatusesand, more particularly, to pipe machining apparatuses for machininglarge diameter pipes.

BACKGROUND

A variety of different types of pipe machining apparatuses exist toperform various machining processes on pipes. One such process includescutting pipes. Large diameter pipes may be cut with a split frame pipemachining apparatus, which includes two frame halves that surround thepipe from respective sides and are coupled together around the pipe.Such a pipe cutter includes a tool or cutting device that encircles thepipe and moves toward the pipe in small increments during the cuttingprocess in order to slowly cut into the pipe. Eventually, after manysmall increments of adjustment toward the pipe, the pipe will becompletely cut.

The frame halves of a split frame pipe machining apparatus are generallysemi-circular in shape and each frame half includes two split linemating surfaces. The split line mating surfaces of the two halves cometogether and engage each other when the two halves are coupled together.Dowel pins project from one of the split line mating surfaces on eachside of the halves and associated dowel holes are defined in the otherof the split line mating surfaces on each side of the halves. The dowelpins are received in the dowel holes to properly align the two framehalves prior to coupling the two halves together. In order for the dowelpins to be received in the dowel holes, the pins must first be alignedwith the holes, then moved into the holes. Since numerous dowel pins areincluded on both sides of the halves, alignment of numerous pin-and-holepairings must be achieved before the pins can be moved into the holes.Aligning numerous pin-and-hole pairings can be a cumbersome task.Moreover, binding can occur if the dowel pins are not properly alignedwith the dowel holes, thereby making assembly and disassembly of the twoframe halves difficult. Furthermore, a high degree of machining accuracyis required when forming the split line mating surfaces. That is, thesplit line matting surfaces must be parallel to a rotational axis of thepipe machining apparatus to ensure proper mating and coupling.

SUMMARY

The present disclosure is defined by the following claims, and nothingin this section should be taken as a limitation on those claims.

In one aspect, a pipe machining apparatus is provided and includes afirst section including a first portion of a frame and a first portionof a tool carrier, and a second section including a second portion ofthe frame and a second portion of the tool carrier. The first sectionand the second section are adapted to be coupled together around a pipe,and, with the first and second sections coupled together, the frame isfixed relative to the pipe and the tool carrier is adapted to moverelative to the frame and the pipe. The pipe machining apparatus alsoincludes a coupling member adapted to couple the first section and thesecond section together. The coupling member includes a first housingmember coupled to the first section, a second housing member coupled tothe second section, an arm movably coupled to the first housing member,and an engagement member coupled to the arm. The arm is adapted to movebetween a coupled condition, in which the engagement member engages thesecond housing member, and an uncoupled condition, in which theengagement member does not engage the second housing member.

In one aspect, a coupling member for coupling together a first sectionand a second section of a pipe machining apparatus is provided. Thecoupling member includes a first housing member adapted to couple to thefirst section, a second housing member adapted to couple to the secondsection, an arm movably coupled to the first housing member, and anengagement member coupled to the arm. The arm is adapted to move betweena coupled condition, in which the engagement member engages the secondhousing member, and an uncoupled condition, in which the engagementmember does not engage the second housing member.

In one aspect, a method of assembling a pipe machining apparatusincluding a first section and a second section is provided. The methodincludes moving the first section toward the second section and engaginga first housing member of a coupling member with a second housing memberof the coupling member. The first housing member is coupled to the firstsection and the second housing member is coupled to the second section.The method also includes moving an arm coupled to the first housingmember to a coupled condition, in which an engagement member of the armengages the second housing member, from an uncoupled condition, in whichthe engagement member does not engage the second housing member.

In one aspect, a pipe machining apparatus is provided and includes afirst section including a first portion of a frame and a first portionof a tool carrier, and a second section including a second portion ofthe frame and a second portion of the tool carrier. The first sectionand the second section are adapted to be coupled together around a pipe,and, with the first and second sections coupled together, the frame isfixed relative to the pipe and the tool carrier is adapted to moverelative to the frame and the pipe. The apparatus has a profile definedby an interior diameter of the frame and an exterior diameter of theframe. The apparatus also includes a coupling member adapted to couplethe first section and the second section together. The coupling memberis moveable between a coupled condition, in which the coupling membercouples the first section and the second section together, and anuncoupled condition, in which the coupling member does not couple thefirst section and the second section together. The coupling memberremains within the profile of the apparatus in both the coupledcondition and the uncoupled condition.

In one aspect, the coupling member includes a moveable arm, and the armremains within the profile of the apparatus in both the coupledcondition and the uncoupled condition.

In one aspect, the coupling member includes a first housing membercoupled to the first section, a second housing member coupled to thesecond section, an arm movably coupled to the first housing member, andan engagement member coupled to and moveable with the arm. Theengagement member engages the second housing member in the coupledcondition and the engagement member does not engage the second housingmember in the uncoupled condition. The arm remains within the profile ofthe apparatus in both the coupled condition and the uncoupled condition.

In one aspect, the first housing member is coupled to the first portionof the tool carrier on the first section and the second housing memberis coupled to the second portion of the tool carrier on the secondsection.

In one aspect, the arm is rotatably coupled to the first housing member.

In one aspect, the arm includes a threaded portion and the engagementmember is adapted to threadably move along the threaded portion of thearm.

In one aspect, the first housing member includes a projection and thesecond housing member includes a receptacle adapted to receive theprojection therein.

In one aspect, the projection includes an angled surface. Duringassembly of the first and second sections, the angled surface of theprojection and the receptacle are adapted to engage each other to movethe first and second sections into proper alignment for couplingtogether.

In one aspect, the coupling member is a first coupling member. The pipemachining apparatus further includes a second coupling membercooperating with the first coupling member to couple the first sectionand the second section together. The second coupling member includes athird housing member coupled to the first section, a fourth housingmember coupled to the second section, a second arm movably coupled tothe fourth housing member, and a second engagement member coupled to thesecond arm. The second engagement member engages the third housingmember in the coupled condition and the second engagement member doesnot engage the third housing member in the uncoupled condition. Thesecond arm remains within the profile of the apparatus in both thecoupled condition and the uncoupled condition.

In one aspect, the coupling member is a first coupling member. The pipemachining apparatus further includes a second coupling member. Thesecond coupling member is moveable between a coupled condition, in whichthe second coupling member couples the first section and the secondsection together, and an uncoupled condition, in which the secondcoupling member does not couple the first section and the second sectiontogether. The second coupling member remains within the profile of theapparatus in both the coupled condition and the uncoupled condition.

In one aspect, the first coupling member includes a first moveable armand the second coupling member includes a second moveable arm. The firstand second arms remain within the profile of the apparatus in both thecoupled condition and the uncoupled condition.

In one aspect, the first section and the second section aresubstantially semi-circular in shape.

In one aspect, a pipe machining apparatus is provided and includes afirst section including a first portion of a frame and a first portionof a tool carrier. The first section defines an aperture therein. Theapparatus also includes a second section including a second portion ofthe frame and a second portion of the tool carrier. The second sectiondefines a bore therein. The first section and the second section areadapted to be coupled together around a pipe, and, with the first andsecond sections coupled together: the frame is fixed relative to thepipe; the tool carrier is adapted to move relative to the frame and thepipe; and the aperture and the bore are aligned with each other. Theapparatus further includes a coupling member positioned in the alignedaperture and bore to selectively couple the first section and the secondsection together. The coupling member is moveable between a coupledcondition, in which the coupling member couples the first section andthe second section together, and an uncoupled condition, in which thecoupling member does not couple the first section and the second sectiontogether.

In one aspect, the aperture includes internal threads and the couplingmember includes a threaded portion. The threaded portion of the couplingmember engages the internal threads of the aperture in the coupledcondition to threadably couple the first and second sections together.

In one aspect, the apparatus further includes a resilient member. Theresilient member engages and retains the coupling member in theuncoupled position to inhibit movement of the coupling member to thecoupled condition.

In one aspect, the coupling member defines a slot. The resilient memberis positioned in the slot when the coupling member is in the uncoupledcondition and wherein the resilient member is not positioned in the slotwhen the coupling member is in the coupled condition.

In one aspect, the apparatus further includes a retainer positioned inthe bore to retain the resilient member in the bore.

In one aspect, the apparatus further includes a key member configured toinhibit the first section and the second section from twisting relativeto each other.

In one aspect, one of the first section and the second section define akey aperture therein. The key member is positioned in the key aperture.

In one aspect, the key member is coupled to the one of the first sectionand the second section by a fastener.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be better understood with reference to the followingdrawings and description. The components in the figures are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the disclosure.

FIG. 1 is a top front perspective view of an exemplary pipe machiningapparatus coupled to a pipe, the pipe machining apparatus is shown witha pair of exemplary coupling members in a coupled condition, inaccordance with one embodiment.

FIG. 2 is a bottom rear perspective view of the pipe machining apparatusillustrated in FIG. 1, in accordance with one embodiment.

FIG. 3 is a front view of the pipe machining apparatus illustrated inFIG. 1 with a portion thereof broken away to show internal components ofthe pipe machining apparatus, and one of the coupling membersillustrated in FIG. 1 is shown in a coupled condition, in accordancewith one embodiment.

FIG. 4 is a front view of the pipe machining apparatus illustrated inFIG. 1 with two sections of the pipe machining apparatus disassembledfrom one another and the pair of exemplary coupling members in anuncoupled condition, in accordance with one embodiment.

FIG. 5 is a bottom perspective view of a portion of the pipe machiningapparatus shown in FIG. 1 with the two sections of the pipe machiningapparatus disassembled and one of the coupling members shown in anuncoupled condition, in accordance with one embodiment.

FIG. 6 is a top perspective view of a portion of the pipe machiningapparatus shown in FIG. 1 with the two sections of the pipe machiningapparatus disassembled and one of the coupling members shown in anuncoupled condition, in accordance with one embodiment.

FIG. 7 is a left side view of the pipe machining apparatus shown in FIG.1 with the two sections of the pipe machining apparatus assembled andone of the coupling members shown in a coupled condition, in accordancewith one embodiment.

FIG. 8 is an enlarged front view of the pipe machining apparatus shownin FIG. 1 with a portion thereof broken away in accordance withreference line 8-8 in FIG. 7 to illustrate internal components of one ofthe coupling members in a coupled condition, in accordance with oneembodiment.

FIG. 9 is a cross-sectional view taken along line 9-9 in FIG. 7 to showan exemplary detent mechanism of one of the coupling members, inaccordance with one embodiment.

FIG. 10 is a perspective view of an end of one of the split framesections of the pipe machining apparatus shown in FIG. 1 with anexemplary alignment receptacle, in accordance with one embodiment.

FIG. 11 is a perspective view of an end of one of the split framesections of the pipe machining apparatus shown in FIG. 1 with anexemplary alignment projection, in accordance with one embodiment.

FIG. 12 is a top front perspective view of another exemplary pipemachining apparatus coupled to a pipe, the pipe machining apparatus isshown with a pair of exemplary coupling members in a coupled condition,in accordance with one embodiment.

FIG. 13 is a front view of the pipe machining apparatus illustrated inFIG. 12, in accordance with one embodiment.

FIG. 14 is a front view of the pipe machining apparatus illustrated inFIG. 12 with two sections of the pipe machining apparatus disassembledfrom one another and the pair of exemplary coupling members in anuncoupled condition, in accordance with one embodiment.

FIG. 15 is a bottom perspective view of a portion of the pipe machiningapparatus shown in FIG. 12 with the two sections of the pipe machiningapparatus disassembled and one of the coupling members shown in anuncoupled condition, in accordance with one embodiment.

FIG. 16 is a top perspective view of a portion of the pipe machiningapparatus shown in FIG. 12 with the two sections of the pipe machiningapparatus disassembled and one of the coupling members shown in anuncoupled condition, in accordance with one embodiment.

FIG. 17 is a cross-sectional view taken along line 17-17 in FIG. 13, inaccordance with one embodiment.

FIG. 18 is a cross-sectional view taken along line 18-18 in FIG. 12 withone example of a first coupling member shown in a coupled condition, inaccordance with one embodiment.

FIG. 19 is a cross-sectional view similar to FIG. 18 with the firstcoupling member shown in an uncoupled condition, in accordance with oneembodiment.

DETAILED DESCRIPTION

With reference to FIGS. 1-3, there is shown one exemplary embodiment ofa pipe machining apparatus 20 adapted to machine pipes P of varyingdiameters. In some exemplary embodiments, the apparatus 20 completelycuts through pipes P. In other exemplary embodiments, the apparatus 20prepares an end of a pipe P for coupling to another pipe. In still otherexemplary embodiments, the apparatus 20 both completely cuts andprepares a pipe P for coupling to another pipe.

In the illustrated exemplary embodiment, pipe machining apparatus 20 isformed of two joined-together semicircular sections 24A, 24B andincludes a frame 28 and a tool carrier 32. The two sections 24A, 24Btogether comprise the frame 28 and the tool carrier 32 such that a firstportion of the frame 28 and a first portion of the tool carrier 32 isincluded in one section 24A and a second portion of the frame 28 and asecond portion of the tool carrier 32 is included in the other section24B. The frame 28 has a column 36 extending outwardly of the twosemicircular sections 24A, 24B and houses a pinion gear 40 adapted tocouple with a suitable drive motor 44, such as an air motor withsuitable gear reduction means. The frame 28 is adapted to couple and befixed relative to a pipe P, and the tool carrier 32 is rotatablerelative to the fixed frame 28 and the pipe P. The air motor 44 isadapted to rotate the tool carrier 32 relative to the frame 28 through agear train in the column 36. The tool carrier 32 has a circular gearrack 56 for meshing with the pinion gear 40 rotatably mounted in column36. The pinion gear 40 has an opening 60 provided with a polygonalperimeter for receiving a complementary shaped drive head 64 of drivemotor 44. Therefore, it can be seen that drive motor 44 is adapted torotate tool carrier 32 relative to the frame 28 through a gear trainprovided by pinion gear 40 in column 36 and circular gear rack 56 on thetool carrier 32.

The rotatable tool carrier 32 includes one or more tool supports 48 (twotool supports shown in the illustrated exemplary embodiment), whichsupport tools 52 for performing a cutting or machining operation on thepipe P as the tools 52 rotate circumferentially about the pipe P. Themachining operation performed by the tool(s) 52 may form a straight edgeperpendicular to a longitudinal extent of the pipe P, a bevel on an endof the pipe P that is transverse to the longitudinal extent of the pipeP and at an angle other than ninety degrees, or an edge of a pipe Phaving any angle relative to the longitudinal extent of the pipe P.

The apparatus 20 further includes four adjustable clamp members orcoupling members 68 engageable with an exterior of the pipe P and havingsuitable adjustability to couple and concentrically locate the apparatus20 to the pipe P.

As best seen in FIG. 3, tool carrier 32 is rotatably mounted on andsupported by frame 28 by a plurality of roller bearings 72. The rollerbearings 72 ride in a circular bearing race 76 defined in the interiorof tool carrier 32.

A plurality of projections 80 are adjustably movable into and out of apath of an advancement member 84 coupled to each tool support 48 toadvance the tool 52 toward the pipe P. In the illustrated exemplaryembodiment, the apparatus 20 includes a total of two projections 80 forengaging the advancement members 84, however, the apparatus 20 may haveany number of projections 80. Each projection 80 is coupled to a lever88 that may be actuated by a user to selectively move the projection 80into and out of the path of the advancement members 84.

With continued reference to FIGS. 1-3 and additional reference to FIG.4, the apparatus 20 includes a split line 92 where the two sections 24A,24B separate and come together. Each section 24A, 24B includes two ends96 with each end of the tool carrier 32 including a mating surface 100.When the apparatus 20 is assembled as shown in FIG. 3, mating surfaces100 on corresponding ends 96 of tool carrier 32 of the sections 24A, 24Bmay engage each other and the two sections 24A, 24B may be coupledtogether.

The apparatus 20 includes a pair of first coupling members 104, one oneach side of the apparatus 20, that are inline with and coupled to theframe 28. Each of the first coupling members 104 includes a first end108 pivotally coupled to sections 24B of the frame 28 in a recess 112and a second threaded end 116 including an adjustable engagement member120 that may be threaded along the threaded end 116. A second recess 124is defined in both sides of section 24A of the frame 28 and each secondrecess 124 is adapted to receive the engagement member 120 of thecorresponding first coupling member 104. The second recess 124 defines aseat 128 adapted to receive the engagement member 120 and assist withretaining the engagement member 120 in the second recess 124.

With reference to FIGS. 1, 2, and 7, one of the first coupling members104 is illustrated in a coupled condition, in which the engagementmember 120 is positioned in the seat 128 of the second recess 124 andtightened down to assist in securing sections 24A, 24B together. To movethe first coupling member 104 to the uncoupled condition illustrated inFIGS. 4-6, the engagement member 120 is threadably loosened along thethreaded end 116 of the first coupling member 104 to move the engagementmember 120 out of the seat 128, and the first coupling member 104 isrotated about its first end 108 until the engagement member 120 iscompletely out of the second recess 124. The first recess 112 is shapedto facilitate swinging and rotating of the first end 108 of the firstcoupling member 104. Moreover, the first recess 112 can be shaped tocontrol the extent to which the first coupling member 104 rotates towardthe uncoupled condition as illustrated in FIGS. 4-6. The pair of firstcoupling members 104 may be swung between coupled and uncoupledconditions as desired by a user to respectively couple and uncouple thetwo sections 24A, 24B of the apparatus 20.

Referring now to FIGS. 1 and 3-8, the apparatus 20 further includes apair of second coupling members 132, one on each side of the apparatus20, that are coupled to the tool carrier 32. Thus, the pair of secondcoupling members 132 rotate with the tool carrier 32 relative to theframe 28 during operation of the apparatus 20. The pair of secondcoupling members 132 are substantially identical in structure andfunction. Thus, only one of the second coupling members 132 will bedescribed herein in detail. However, the description presented hereinpertaining to one of the second coupling members 132 applies similarlyto both second coupling members 132.

With continued reference to FIGS. 1 and 3-8, each second coupling member132 includes a first housing member 136 coupled to the tool carrier 32on a respective section 24A, 24B of the apparatus 20, a second housingmember 140 coupled to the tool carrier 32 on the other of the sections24A, 24B, and an arm 144 rotatably coupled at a first end 148 thereof tothe first housing member 136.

The first housing member 136 couples to the tool carrier 32 with aplurality of fasteners 152. The first housing member 136 of one of thesecond coupling members 132 is coupled to the tool carrier 32 includedin section 24B of the apparatus 20 and the first housing member 136 ofthe other of the second coupling members 132 is coupled to the toolcarrier 32 included in section 24A of the apparatus 20. The orientationof the first housing member 136 may be adjusted by loosening thefasteners 152, rotating or otherwise moving the first housing member136, then tightening the fasteners 152 to secure the first housingmember 136 to the tool carrier 32. The first housing member 136 includesa mating surface 156 that is substantially flat and defines a recess 160allowing rotation of the arm 144 and controlling the extent to which thearm 144 can rotate toward the uncoupled condition. The first housingmember 136 also includes a projection 164 extending beyond the flatmating surface 156 of the first housing member 136 and beyond the matingsurface 100 of the respective end 96 of the tool carrier 32. Theprojection 164 includes arcuate side surfaces 168 and flat opposingfront and rear surfaces 176, 180. A chamfer or bevel 184 may be definedon edges of the projection 164.

The second housing member 140 couples to the tool carrier 32 with aplurality of fasteners 188. The second housing member 140 of one of thesecond coupling members 132 is coupled to the tool carrier 32 includedin section 24A of the apparatus 20 and the second housing member 140 ofthe other of the second coupling members 132 is coupled to the toolcarrier 32 included in section 24B of the apparatus 20. The orientationof the second housing member 140 may be fixed by a dowel pin 216 incombination with fasteners 188. The second housing member 140 includes amating surface 192 that is substantially flat and defines a recess 196therein allowing rotation of the arm 144 and controlling the extent towhich the arm 144 can rotate toward a coupled condition. A seat 200 isdefined in the second housing member 140 for receiving an engagementmember 204 of the arm 144 and assists with maintaining the arm 144 inthe coupled condition. The seat 200 is generally flat and is disposed onboth sides of the recess 196. The second housing member 140 also definesa receptacle 208 therein for receiving the projection 164 of the firsthousing member 136. The receptacle 208 is defined by a pair of arcuatesurfaces 212, a protrusion 220 on the second housing member 140 definingone side of the receptacle 208, and a surface 224 of the tool carrier 32defining an opposing side of the receptacle 208.

With further reference to FIGS. 1 and 3-8, and additional reference toFIG. 9, the arm 144 is rotatably coupled at one end to a shaft 228,which is coupled to the first housing member 136. The arm 144 includesan aperture 232 there through for receiving the shaft 228. The arm 144also includes an opposing threaded end 236 and the engagement member 204threadably movable along the threaded end 236.

With continued reference to FIGS. 1 and 3-9, the shaft 228 extends alonga longitudinal axis 229 that is oriented substantially parallel to acentral rotational axis 22 of the apparatus 20. The central rotationalaxis 22 of the apparatus 20 may also extend through a longitudinalcenter of a pipe P when the apparatus 20 is coupled to the pipe P. Inother words, the longitudinal axis 229 is generally perpendicular to thesurface 224 of the tool carrier 32. The arm 144 rotates about the axis229 between the coupled condition and the uncoupled condition. The arm144 rotates beyond a profile of the apparatus 20 defined by an interiordiameter 230 of the apparatus 20 and an exterior diameter 231 of theapparatus 20 when the arm 144 is in the uncoupled condition (see FIGS.4-6), but remains within the profile of the apparatus 20 when in thecoupled condition (see FIGS. 3, 8 and 9).

The second coupling member 132 further includes a detent mechanism 240(see FIG. 9) for selectively retaining the arm 144 in the coupledcondition and the uncoupled condition. The detent mechanism 240comprises a pair of spaced-apart indentations 244 defined in one end ofthe arm 144, a retaining member 248, and a biasing member 252. Thebiasing member 248 is disposed in a cavity 256 defined in the firsthousing member 136 and engages the retaining member 248 to bias theretaining member 248 toward the arm 144. With reference to FIG. 9, thesecond coupling member 132 is shown in the coupled condition and theretaining member 248 is biased into one of the indentations 244associated with the coupled condition. After loosening of the engagementmember 204, the arm 144 remains in the orientation illustrated in FIG. 9due to the detent mechanism 240. A user may apply sufficient force tothe arm 144 to overcome the force applied to the arm 144 by the detentmechanism 240 and move the arm 144 toward the uncoupled condition. Whenthe arm 144 moves into the uncoupled condition, the retaining member 248is biased into the other indentation 244 associated with the uncoupledcondition. The detent mechanism 240 maintains the arm 144 in theuncoupled condition until a user applies a sufficient force to overcomethe force applied to the arm 144 by the detent mechanism 240.

The second coupling members 132 perform a variety of functions. First,the second coupling members 132 assist with guiding the two sections24A, 24B into proper alignment with each other in preparation ofcoupling the two sections 24A, 24B together. Second, the second couplingmembers 132 provide a user with a manner of quickly and easily retainingthe sections 24A, 24B together around a pipe P prior to complete andfinal coupling of the two sections 24A, 24B by quickly flipping the arms144 to the coupled condition and the arms 144 being retained in thecoupled condition by the detent mechanism 240. Third, the secondcoupling members 132, along with the first coupling members 104, assistwith finally and completely coupling the two sections 24A, 24B of theapparatus 20 together. Fourth, with the use of the second couplingmembers 132, the mating surfaces 100 of the ends 96 of the tool carrier32 of sections 24A, 24B do not need to be machined or manufactured toinclude such a high degree of tolerance. The second coupling members 132are adapted to achieve other functions not explicitly identified herein,but apparent to those having ordinary skill in the art, and all of suchfunctions are intended to be within the spirit and scope of the presentdisclosure.

Referring now to FIG. 4, the two sections 24A, 24B of the apparatus 20are shown in an uncoupled or disassembled condition. To assemble the twosections 24A, 24B, the ends 96 of the two sections 24A, 24B aregenerally aligned and moved toward one another. With additionalreference to FIGS. 5 and 6, as the ends 96 of the two sections 24A, 24Bdraw close together, the projections 164 of the first housing members136 begin to insert into the receptacles 208 of the second housingmembers 140. The chamfered edges 184 and arcuate surfaces 168 of theprojections 164, along with the complementary shape of the receptacles208, accommodate situations where the two sections 24A, 24B are notexactly properly aligned. More particularly, the projections 164 andreceptacles 208 engage each other and guide the two sections 24A, 24Binto the ultimate proper alignment as the two sections 24A, 24B movetogether. The chamfered edges 184 and arcuate surfaces 168 of theprojections 164 and the shape of the receptacles 208 generally provide aramp engagement such that any portion of the projections 164 can engageany portion of the receptacles 208 and the projections 164 will ridealong the interiors of the receptacles 208 until the projections 164 areguided into and properly seated within the receptacles 208 asillustrated in FIGS. 8 and 9.

Once the first and second housing members 136, 140 are adequatelybrought together, the arm 144 may be swung from the uncoupled conditionillustrated in FIGS. 4-6 to the coupled condition shown in FIGS. 3 and7-9. The retaining member 248 of the detent mechanism 240 inserts intothe indentation 244 associated with the coupled condition to retain thearm 144 in the coupled condition. The engagement member 204 may then bethreaded toward and into the seat 200 of the second housing member 140.The engagement member 204 is threaded until an adequate amount oftightening has been achieved. The first coupling members 104 may also betightened to assist with securing the two sections 24A, 24B together.

When the second coupling members 132 and the two sections 24A, 24B arein the completely coupled condition (see FIGS. 7-9), the arcuatesurfaces 168 of the projection 164 engage the arcuate surfaces 212 ofthe receptacle 208, the flat rear surface 180 of the projection 164engages the surface 224 of the tool carrier 32, and the opposing flatfront surface 176 of the projection 164 engages the protrusion 220 ofthe receptacle 208. Thus, the second housing member 140 has portionsthereof on multiple sides (e.g., top, front, rear, left, and right) ofthe projection 164 of the first housing member 136, thereby inhibitingmovement of the first and second housing members 136, 140 relative toeach other in multiple directions (e.g., forward, rearward, upward,left, and right).

When coupling the two sections 24A, 24B of the apparatus 20 together,some portions of the two sections 24A, 24B near the ends 96 of the twosections 24A, 24B need to abut and mate to facilitate a proper couplingof the two sections 24A, 24B. In conventional split frame pipe machiningapparatuses, mating surfaces at the ends of the tool carrier are thesurfaces that must abut and mate in an appropriate manner in order toadequately couple the two sections together. If the mating surfaces ofthe tool carrier ends were not properly toleranced or if the dowel pinswere not appropriately inserted into the associated holes (conventionalmanner of aligning ends of sections—see Background), the two sectionscould not be properly coupled. Ensuring that the mating surfaces of thetool carrier ends of the two sections were properly machined to anappropriate degree of tolerance or ensuring the dowel pins andassociated holes were adequately aligned and inserted can be acomplicated, time consuming, and costly process, and even after takingall of these necessary steps still may not result in proper coupling ofthe ends of the sections.

The apparatus 20 illustrated and described herein relies on the matingsurfaces 156, 192 of the first and second housing members 136, 140 toabut and mate, rather than the mating surfaces 100 of the tool carrierends 96 of the two sections 24A, 24B, to facilitate a proper coupling ofthe two sections 24A, 24B. The process for ensuring proper tolerancingof the mating surfaces 156, 192 of the first and second housing members136, 140 can be easier, quicker, and less costly. Additionally, theorientation of the first housing member 136 may be adjusted relative tothe fixed second housing member 140 to ensure proper mating of themating surfaces 156, 192. By utilizing the mating surfaces 156, 192 ofthe first and second housing members 136, 140, the mating surfaces 100of the tool carrier ends 96 of the two sections 24A, 24B do not need tobe tolerance to such a high degree, thereby potentially saving time,effort, and money when manufacturing the apparatus 20.

Referring now to FIGS. 5, 6, 10, and 11, the apparatus 20 furtherincludes an alignment projection 260 and an alignment receptacle 264complimentarily shaped to receive the alignment projection 260 therein.In the illustrated exemplary embodiment, the alignment projection 260and the alignment receptacle 264 are inserts coupled to the frame 28 inends of the two sections 24A, 24B. In other exemplary embodiments, thealignment projection 260 and alignment receptacle 264 may be unitarilyformed as one-piece with the frame 28 of the two sections 24A, 24B.Also, in embodiments where the alignment projection 260 and alignmentreceptacle 264 are inserts, the inserts may be made of a differentmaterial than the frame 28 such as, for example, the frame 28 may bealuminum and the inserts may be steel. Each alignment projection 260includes two portions, with each portion including angled exteriorsurfaces 268 and chamfered edges 272 to provide a ramp-like member. Eachalignment receptacle 264 includes two compartments, one for receiving acorresponding one of the two portions of the alignment projection 260.The compartments include angled side surfaces 276 that also act like aramp surface. Upon coupling the two sections 24A, 24B together, thealignment projections 260 insert into the alignment receptacles 264,which may bring the angled exterior surfaces 268 of the alignmentprojections 260 into the angled side surfaces 276 of the receptacles264. The ramp-like surfaces ride along each other to position thealignment projections 260 in the proper location within the alignmentreceptacles 264, thereby also positioning the two sections 24A, 24B inthe proper position relative to one another. The alignment projections260 and alignment receptacles 264 cooperate with the second couplingmembers 132 to ensure easy, quick, and proper alignment of the twosections 24A, 24B for coupling.

With reference to FIGS. 12-19, there is shown another exemplaryembodiment of a pipe machining apparatus 20′ adapted to machine pipes P′of varying diameters. Components of the pipe machining apparatus 20′shown in FIGS. 12-19 similar to components of the pipe machiningapparatus 20 shown in FIGS. 1-11 include the same reference number and a“′”.

With continued reference to FIGS. 12-19, the apparatus 20′ includes asplit line 92′ where the two sections 24A′, 24B′ separate and cometogether. Each section 24A′, 24B′ includes two ends 96′ with each end ofthe tool carrier 32′ including a mating surface 100′. When the apparatus20′ is assembled as shown in FIG. 13, mating surfaces 100′ oncorresponding ends 96′ of tool carrier 32′ of the sections 24A′, 24B′may engage each other and the two sections 24A′, 24B′ may be coupledtogether.

The apparatus 20′ includes a pair of first coupling members 300, one oneach side of the apparatus 20′, that are inline with and coupled to theframe 28′. In this example, the break line 92′ is not linear or planarand, instead, has a generally zig-zag shape. In the illustrated example,ends 96′ of the two sections 24A′, 24B′ include a first pair of mattingsurfaces 100A′ arranged transversely and non-radial to the centrallongitudinal axis 22′ of the apparatus 20′ in a first direction, asecond pair of mating surfaces 100B′ arranged transversely andnon-radial to the central longitudinal axis 22′ in a second direction,and a third pair of mating surfaces 100C′ arranged in a third directiongenerally perpendicular to and radial to the central longitudinal axis22′.

In the illustrated example, the first coupling members 300 are threadedfasteners. In other examples, the first coupling members 300 may beother types of coupling members coupling the ends 96′ of the twosections 24A′, 24B′ together in other manners. The first couplingmembers 300 and associated structure of the apparatus 20′ and,therefore, only one of the first coupling members 300 will be describedhere in detail.

Each of the first coupling members 300 includes a head 302 and a shank304. The head 302 is positioned at a first end of the first couplingmember 300 and a threaded portion 306 is positioned at a second end ofthe first coupling member 300. The threaded portion 306 cooperates withan internal threaded aperture 308 defined in the frame 28′ (one aperture308 defined in an end 96′ of one section 24A′ and one aperture 308defined in an end 96′ of the other section 24B′). A bore 310 is definedin each end 96′ of two sections 24A′, 24B′ and is alignable with arespective one of the apertures 308. The first coupling members 300 arereceived in the aperture 308 and bore 310 when they are aligned and themating surfaces 100A′, 100B′, 100C′ may be respectively engaged.

The shank 304 has a portion 312 with a first size or first diameter, aportion 314 with a second size or second diameter, and a slot 316defined therein to provide a third size or third diameter. A resilientmember 318 is retained within the bore 310 by a retainer 320. In theillustrated example, the resilient member 318 is an O-ring. In otherexamples, the resilient member 318 may be other types of resilientmembers. A first bushing 322 is positioned in an end of the aperture 308and a second bushing 324 is positioned in an end of the bore 310.

A key aperture 326 is defined in the frame 28′ near ends 96′ of the twosections 24A′, 24B′. A key member 328 is positioned in the key aperture326 and is coupled to the frame 28′ with a fastener 330. In theillustrated example, the fastener 330 is a threaded fastener and the keymember 328 is threadably coupled to the frame 28′. In other examples,the fastener 330 may be other types of fasteners and the key member 328may be coupled to the frame 28′ in other manners. The key member 328 isconfigured to inhibit the ends 96′ of the two sections 24A′, 24B fromtwisting relative to each other.

The first coupling members 300 are moveable between a coupled condition(see FIG. 18) and an uncoupled condition (see FIG. 19) to selectivelycouple ends 96′ of the two sections 24A′, 24B′ together. In the coupledcondition shown in FIG. 18, the head 302 of the first coupling member300 engages the retainer 320 and the threaded portion 306 is securelyand tightly threaded into the threaded aperture 308 to securely couplethe ends 96′ of the two sections 24A′, 24B′ together. The portion 314 ofthe shank 304 having the second diameter is positioned within or alignedwith the first and second bushings 322, 324. The second diameter 314 ofthe shank 304 and internal cavities 332, 334 of the bushings 322, 324are complementary sized to provide a sufficiently close relationship.

To move the first coupling member 300 to the uncoupled position shown inFIG. 19, the first coupling member 300 is unthreaded from the internallythreaded aperture 308 and retracted out of the bore 310 until theresilient member 318 is moved into the slot 316 defined in the shank304. Engagement between the resilient member 318 and the slot 316frictionally retain the first coupling member 300 in the uncoupledposition until a user overcomes the friction engagement between theresilient member 318 and the slot 316.

Referring now to FIGS. 12-17, the apparatus 20 further includes a pairof second coupling members 400, one on each side of the apparatus 20′,that are coupled to the tool carrier 32′. Thus, the pair of secondcoupling members 400 rotate with the tool carrier 32′ relative to theframe 28′ during operation of the apparatus 20′. The pair of secondcoupling members 400 are substantially identical in structure andfunction. Thus, only one of the second coupling members 400 will bedescribed herein in detail. However, the description presented hereinpertaining to one of the second coupling members 400 applies similarlyto both second coupling members 400.

With continued reference to FIGS. 12-17, each second coupling member 400includes a first housing member 404 coupled to the tool carrier 32′ on arespective section 24A′, 24B′ of the apparatus 20′, a second housingmember 408 coupled to the tool carrier 32′ on the other of the sections24A′, 24B′, and an arm 412 rotatably coupled at a first end 416 thereofto the first housing member 404.

The first housing member 404 couples to the tool carrier 32′ with aplurality of fasteners 420. The first housing member 404 of one of thesecond coupling members 400 is coupled to the tool carrier 32′ includedin section 24B′ of the apparatus 20′ and the first housing member 404 ofthe other of the second coupling members 400 is coupled to the toolcarrier 32′ included in section 24A′ of the apparatus 20′. Theorientation of the first housing member 404 may be adjusted by looseningthe fasteners 420, rotating or otherwise moving the first housing member404, then tightening the fasteners 420 to secure the first housingmember 404 to the tool carrier 32′. The first housing member 404includes a mating surface 424 that is substantially flat and defines arecess 428 allowing rotation of the arm 412 and controlling the extentto which the arm 412 can rotate toward the uncoupled condition. Thefirst housing member 404 also includes a projection 432 extending beyondthe flat mating surface 424 of the first housing member 404 and beyondthe mating surface 100′ of the respective end 96′ of the tool carrier32′. The projection 432 includes angled surfaces 436 to provide achamfer or bevel 440 on the projection 432.

The second housing member 408 couples to the tool carrier 32′ with aplurality of fasteners 444. The second housing member 408 of one of thesecond coupling members 400 is coupled to the tool carrier 32′ includedin section 24A′ of the apparatus 20′ and the second housing member 408of the other of the second coupling members 400 is coupled to the toolcarrier 32′ included in section 24B′ of the apparatus 20′. The secondhousing member 408 includes a mating surface 448 that is substantiallyflat and defines a recess 452 therein allowing rotation of the arm 412and controlling the extent to which the arm 412 can rotate toward acoupled condition. A seat 456 is defined in the second housing member408 for receiving an engagement member 460 of the arm 412 and assistswith maintaining the arm 412 in the coupled condition. The seat 456 isgenerally flat and is disposed on both sides of the recess 452. Thesecond housing member 408 also defines a receptacle 464 therein forreceiving the projection 432 of the first housing member 404.

With further reference to FIGS. 12-17, the arm 412 is rotatably coupledat one end to a shaft 468, which is coupled to the first housing member404. The arm 412 includes an aperture 472 there through for receivingthe shaft 468. The arm 412 also includes an opposing threaded end 476and the engagement member 460 is threadably movable along the threadedend 476.

With continued reference to FIGS. 12-17, the shaft 468 extends along alongitudinal axis 489 that is oriented transversely or radially to acentral rotational axis 22′ of the apparatus 20′. The central rotationalaxis 22′ of the apparatus 20′ may also extend through a longitudinalcenter of a pipe P′ when the apparatus 20′ is coupled to the pipe P′. Inother words, the longitudinal axis 489 is generally parallel to asurface 224′ of the tool carrier 32′. The arm 412 rotates about the axis489 between the coupled condition and the uncoupled condition. The arm412 remains within the profile of the apparatus 20′ defined by aninterior diameter 492 of the apparatus 20′ and an exterior diameter 496of the apparatus 20′ when the arm 412 is in both the coupled conditionand the uncoupled condition.

The second coupling members 400 perform a variety of functions. First,the second coupling members 400 assist with guiding the two sections24A′, 24B′ into proper alignment with each other in preparation ofcoupling the two sections 24A′, 24B′ together. Second, the secondcoupling members 400 provide a user with a manner of quickly and easilyretaining the sections 24A′, 24B′ together around a pipe P prior tocomplete and final coupling of the two sections 24A′, 24B′ by quicklyflipping the arms 412 to the coupled condition. Third, the secondcoupling members 400, along with the first coupling members 300, assistwith finally and completely coupling the two sections 24A′, 24B′ of theapparatus 20′ together. Fourth, with the use of the second couplingmembers 400, the mating surfaces 100′ of the ends 96′ of the toolcarrier 32′ of sections 24A′, 24B′ do not need to be machined ormanufactured to include such a high degree of tolerance. The secondcoupling members 400 are adapted to achieve other functions notexplicitly identified herein, but apparent to those having ordinaryskill in the art, and all of such functions are intended to be withinthe spirit and scope of the present disclosure.

Referring now to FIG. 14, the two sections 24A′, 24B′ of the apparatus20′ are shown in an uncoupled or disassembled condition. To assemble thetwo sections 24A′, 24B′, the ends 96′ of the two sections 24A′, 24B′ aregenerally aligned and moved toward one another. With additionalreference to FIGS. 15 and 16, as the ends 96′ of the two sections 24A′,24B′ draw close together, the projections 432 of the first housingmembers 404 begin to insert into the receptacles 464 of the secondhousing members 408. The chamfers 440 and angled surfaces 436 of theprojections 432, along with the complementary shape of the receptacles464, accommodate situations where the two sections 24A, 24B are notexactly properly aligned. More particularly, the projections 432 andreceptacles 464 engage each other and guide the two sections 24A′, 24B′into the ultimate proper alignment as the two sections 24A′, 24B′ movetogether. The chamfers 440 and angled surfaces 436 of the projections432 and the shape of the receptacles 464 generally provide a rampengagement such that any portion of the projections 432 can engage anyportion of the receptacles 464 and the projections 432 will ride alongthe interiors of the receptacles 464 until the projections 432 areguided into and properly seated within the receptacles 464 asillustrated in FIGS. 12, 13 and 17.

Once the first and second housing members 404, 408 are adequatelybrought together, the arm 412 may be swung from the uncoupled conditionillustrated in FIGS. 14-16 to the coupled condition shown in FIGS. 12,13 and 17. The engagement member 460 may then be threaded toward andinto the seat 456 of the second housing member 408. The engagementmember 460 is threaded until an adequate amount of tightening has beenachieved. The first coupling members 300 may also be tightened to assistwith securing the two sections 24A′, 24B′ together.

When the second coupling members 400 and the two sections 24A′, 24B′ arein the completely coupled condition (see FIGS. 12, 13 and 17), theprojection 432 is positioned in and engages the receptacle 464, a flatrear surface 480 of the projection 432 engages the surface 224′ of thetool carrier 32′, and an opposing flat front surface 484 of theprojection 432 engages an interior surface 488 of the receptacle 464.Thus, the second housing member 408 has portions thereof on multiplesides (e.g., top, front, rear, etc.) of the projection 432 of the firsthousing member 404, thereby inhibiting movement of the first and secondhousing members 404, 408 relative to each other in multiple directions(e.g., forward, rearward, upward, etc.).

When coupling the two sections 24A′, 24B′ of the apparatus 20′ together,some portions of the two sections 24A′, 24B′ near the ends 96′ of thetwo sections 24A′, 24B′ need to abut and mate to facilitate a propercoupling of the two sections 24A′, 24B′. In conventional split framepipe machining apparatuses, mating surfaces at the ends of the toolcarrier are the surfaces that must abut and mate in an appropriatemanner in order to adequately couple the two sections together. If themating surfaces of the tool carrier ends were not properly toleranced orif the dowel pins were not appropriately inserted into the associatedholes (conventional manner of aligning ends of sections—see Background),the two sections could not be properly coupled. Ensuring that the matingsurfaces of the tool carrier ends of the two sections were properlymachined to an appropriate degree of tolerance or ensuring the dowelpins and associated holes were adequately aligned and inserted can be acomplicated, time consuming, and costly process, and even after takingall of these necessary steps still may not result in proper coupling ofthe ends of the sections.

In one example, the apparatus 20′ illustrated and described hereinrelies on the mating surfaces 424, 448 of the first and second housingmembers 404, 408 to abut and mate, rather than the mating surfaces 100′of the tool carrier ends 96′ of the two sections 24A′, 24B′, tofacilitate a proper coupling of the two sections 24A′, 24B′. The processfor ensuring proper tolerancing of the mating surfaces 424, 448 of thefirst and second housing members 404, 408 can be easier, quicker, andless costly. In one example, the orientation of the first housing member404 may be adjusted relative to the fixed second housing member 408 toensure proper mating of the mating surfaces 424, 448. By utilizing themating surfaces 424, 448 of the first and second housing members 404,408, the mating surfaces 100′ of the tool carrier ends 96′ of the twosections 24A′, 24B′ do not need to be toleranced to such a high degree,thereby potentially saving time, effort, and money when manufacturingthe apparatus 20′.

The Abstract of the disclosure is provided to allow the reader toquickly ascertain the nature of the technical disclosure. It issubmitted with the understanding that it will not be used to interpretor limit the scope or meaning of the claims. In addition, in theforegoing Detailed Description, it can be seen that various features aregrouped together in various embodiments for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed embodiment. Thus, the following claimsare hereby incorporated into the Detailed Description, with each claimstanding on its own as a separately claimed subject matter.

While various embodiments of the disclosure have been described, it willbe apparent to those of ordinary skill in the art that other embodimentsand implementations are possible within the scope of the disclosure.Accordingly, the disclosure is not to be restricted except in light ofthe attached claims and their equivalents.

The invention claimed is:
 1. A pipe machining apparatus defining acentral axis extending through a center thereof, the pipe machiningapparatus comprising: a first section including a first portion of aframe and a first portion of a tool carrier, an end of the first portionof the frame including a first mating surface arranged transversely andnon-radial to the central axis, the first mating surface having a firstsurface portion and a second surface portion, and the first surfaceportion is non-planar with the second surface portion, and a couplingaperture is defined in the first surface portion of the first matingsurface; a second section including a second portion of the frame and asecond portion of the tool carrier, the first section and the secondsection are configured to be coupled together around a pipe, and an endof the second portion of the frame includes a second mating surfacearranged transversely and non-radial to the central axis, the secondmating surface having a first surface portion and a second surfaceportion, and the first surface portion is non-planar with the secondsurface portion, and a bore is defined in the first surface portion ofthe second mating surface; a first coupling member adapted to couple thefirst section and the second section together, the first coupling memberincluding a first housing member coupled to the first section, a secondhousing member coupled to the second section, an arm movably coupled tothe first housing member, and an engagement member coupled to the arm,wherein the arm is adapted to move between a coupled condition, in whichthe engagement member engages the second housing member, and anuncoupled condition, in which the engagement member does not engage thesecond housing member, a second coupling member configured to bepositioned in the coupling aperture and the bore; a key memberconfigured to be coupled to the second surface portion of one of thefirst mating surface and the second mating surface; a key aperture inthe other of the second surface portion of the first mating surface andthe second mating surface, and the key member being further configuredto be positioned in the key aperture and, with the first and secondsections coupled together: the frame is fixed relative to the pipe andthe central axis extends through a longitudinal center of the pipe, thetool carrier supports a tool support that is configured to support atool, and the tool carrier is configured to rotate the tool supportabout the central axis relative to the frame and the pipe, and thecoupling aperture and the bore are aligned with each other; and thesecond coupling member is positioned in the aligned coupling apertureand bore to selectively couple the first section and the second sectiontogether, wherein the second coupling member is movable between acoupled condition, in which the second coupling member couples the firstsection and the second section together, and an uncoupled condition, inwhich the second coupling member does not couple the first section andthe second section together; and together, the key member is coupled tothe second surface portion of one of the first mating surface and thesecond mating surface and is positioned in the key aperture, the keymember being configured to inhibit the first section and the secondsection from twisting relative to each other, and the engagement memberengages the second housing member.
 2. The pipe machining apparatus ofclaim 1, wherein wherein the key member is elongated and has a lengthgreater than a width, and the key aperture is elongated and has a lengthgreater than a width, the length of the key aperture being greater thanthe length of the key member, and the key member is configured to bepositioned in the key aperture.
 3. The pipe machining apparatus of claim1, wherein the key member is coupled to the second surface portion ofthe one of the first mating surface and the second mating surface by afastener.
 4. The pipe machining apparatus of claim 1, further comprisinga resilient member, wherein the resilient member engages and retains thesecond coupling member in the uncoupled position to inhibit movement ofthe second coupling member to the coupled condition, and wherein thesecond coupling member defines a slot, wherein the resilient member ispositioned in the slot when the second coupling member is in theuncoupled condition and wherein the resilient member is not positionedin the slot when the second coupling member is in the coupled condition.5. The pipe machining apparatus of claim 4, further comprising aretainer positioned in the bore to retain the resilient member in thebore.
 6. The pipe machining apparatus of claim 1, wherein the couplingaperture includes internal threads and the second coupling memberincludes a threaded portion, wherein the threaded portion of the secondcoupling member engages the internal threads of the coupling aperture inthe coupled condition to threadably couple the first and second sectionstogether.
 7. The pipe machining apparatus of claim 1, wherein the keymember is coupled to the one of the first mating surface and the secondmating surface by a fastener.
 8. The pipe machining apparatus of claim1, wherein with the first and second sections coupled together: thefirst and second sections define an outer circumference of the pipemachining apparatus and an inner circumference of the pipe machiningapparatus, and the longitudinal extent of the second coupling member isnon-tangential to the inner circumference of the pipe machiningapparatus and is configured to intersect the outer circumference of thepipe machining apparatus.
 9. The pipe machining apparatus of claim 8,wherein the coupling aperture includes internal threads and the secondcoupling member includes a threaded portion, wherein the threadedportion of the second coupling member engages the internal threads ofthe coupling aperture in the coupled condition to threadably couple thefirst and second sections together.
 10. The pipe machining apparatus ofclaim 8, wherein the second coupling member includes a head at a firstend of the second coupling member and threads at a second end of thesecond coupling member, wherein the head of the second coupling memberis positioned closer to the outer circumference of the pipe machiningapparatus than the inner circumference, and wherein the threads of thesecond coupling member are positioned closer to the inner circumferenceof the pipe machining apparatus than the outer circumference.